The present invention relates to a curable organopolysiloxane composition and a method of manufacturing a semiconductor device using the composition. More specifically, the invention relates to a curable organopolysiloxane composition for forming a cured body of non-uniform properties with hardness of the surface layer higher than the hardness of the internal material. The invention also relates to an efficient method of manufacturing a semiconductor device having improved reliability due to a non-uniform coating in which the surface layer has hardness higher than that of the internal material.
It is known to coat surfaces of semiconductor devices with coating agents in the form of a curable organopolysiloxane composition containing at least two or more silicon-bonded hydrogen atoms in one molecule, an organopolysiloxane with two or more alkenyl groups in one molecule, and a hydrosilylation metal catalyst. Such use results from the fact that the aforementioned coating agent can be cured by quick heating with the formation of a cured body of uniform properties with excellent electrical characteristics.
However, the following contradiction has to be solved: to protect a semiconductor device from external stress, the coating layer should be hard, while to protect the semiconductor device from internal stress, the aforementioned coating should have low hardness. It is understood that these two requirements cannot be satisfied at the same time.
It has been proposed, in Japanese Laid-Open Patent Application (Kokai) Sho 58-163,652, to solve the above problems by coating a semiconductor device with a cured layer of non-uniform properties having the surface layer harder than the inner material. This is achieved by using a curable organopolysiloxane composition comprising at least an organopolysiloxane with two or more silicon-bonded hydrogen atoms in one molecule, an organopolysiloxane with two or more alkenyl groups in one molecule, and a hydrosilylation metal catalyst, coating the surface of a semiconductor device with at least one component of the aforementioned composition, diffusing the remaining components into the coating, and curing the composition. A disadvantage of the above method is that it is difficult to control hardness of the coating and that the process is complicated.
It is an object of the present invention to provide a curable organopolysiloxane composition for forming a cured body of non-uniform properties with hardness of the surface layer higher than the hardness of the internal material. It is another object to provide an efficient method of manufacturing a semiconductor device having improved reliability due to a non-uniform coating in which the surface layer has hardness higher than that of the internal material.
The above problems are solved by the present invention that provides a curable organopolysiloxane composition comprising at least the following components:
(A) an organopolysiloxane with two or more silicon-bonded hydrogen atoms contained in one molecule in an amount not exceeding 0.05 wt. %;
(B) an organopolysiloxane with two or more alkenyl groups in one molecule {alkenyl groups of this components are used in an amount of 0.01 to 1 mole per 1 mole of silicon-bonded hydrogen atoms contained in said component (A)}, and
(C) a hydrosilylation-reaction metal catalyst (with a content of metal atoms within the range of 0.01 to 1,000 ppm in terms of weight units).
Furthermore, the method of the invention for manufacturing a semiconductor device is characterized by coating the surface of a semiconductor device with the aforementioned curable organopolysiloxane composition, and then curing the coating.